JP4660231B2 - Surface treatment method and method of manufacturing electronic component using the same - Google Patents

Description

  The present invention relates to a surface treatment method for plating a desired portion of a substrate and a method for manufacturing an electronic component using the same.

  A contact layer of an electronic component such as a connector is provided with a plating layer in order to obtain reliability of electrical contact with a circuit board or other electronic components. The connector contact part is obtained by, for example, punching a plate material into a shape including a base having a desired shape such as a belt and a support frame in advance (hereinafter, the plate material processed in this manner is referred to as a strip material). It is obtained by plating the entire surface or a part of the substrate, and then separating the necessary part used as the contact part of the connector from the support frame of the strip material.

  There are many types of connectors. For example, a board mounting connector includes a solder joint used for soldering to a board, a connector that extends from the solder joint, and is provided in another pair. And a longitudinal connector fitting portion used for fitting. The mounting of the board mounting connector to the board is performed by soldering the solder joint. At the time of this solder joining, there is a problem that so-called solder rise occurs in which the molten solder reaches the connector fitting portion, and the reliability of electrical contact between the board and the connector is impaired. Recently, along with downsizing and higher functionality of electronic devices such as information home appliances, contact parts of electronic components have been miniaturized, and defects caused by soldering are more likely to occur in the soldering process. ing.

  In addition, if solder rise occurs during solder joining, the molten solder adheres to the resin case of the connector, and the temperature may adversely affect the resin case. Conventionally, Sn—Pb solder composed of tin and lead has been used as the solder used here, but so-called lead-free solder that does not contain lead is used in consideration of the influence on the global environment. It is supposed to be. Since lead-free solder has a higher melting point than Sn-Pb solder, the adverse effect on the resin case of the connector due to the rise of solder during solder joining is great.

  As a technique for solving the above-mentioned problems due to the solder rise, a region where the wettability with the solder is inferior to the solder joint between the solder joint of the connector and the connector fitting part (hereinafter referred to as low wettability) It is proposed to form a region). A connector having such a low wettability region is, for example, a metal that is poor in wettability with a solder such as nickel (hereinafter referred to as a low wettability metal) over the entire base portion of a strip material that is a base material of the connector. After plating, a predetermined portion for forming a solder joint is formed by partial plating with a metal excellent in wettability with solder such as gold (hereinafter referred to as a high wettability metal). The portion plated with this high wettability metal becomes a high wettability region used as a solder joint, and the portion where the low wettability metal is exposed without plating with the high wettability metal is the low wettability region. It becomes.

  In such a connector, when soldering to the solder joint, the melted solder is prevented from protruding by the low wettability region and does not reach the connector fitting part, so that solder rises in the connector fitting part. It is possible to implement without making it.

  As a method of partial plating used for manufacturing contact parts having such a low wettability region, the level of the plating solution is controlled, and only the portion to be plated is immersed in the plating solution for plating. There is a liquid level control method to be performed. In the liquid level control method, although it is possible to perform partial plating on the entire surface of the longitudinal portion of the substrate at once, the tolerance of the width of the formed plating layer is as large as about ± 1.0 mm. There is a problem that it cannot be used for plating.

  As another method, there is a masking method in which plating is performed by so-called masking that covers a portion that is not plated (hereinafter also referred to as a plating-unnecessary portion). The masking method includes a tape masking method in which a plating-resistant tape is attached to a plating-unnecessary portion for plating, and a belt-shaped mask having an opening corresponding to the plating-unnecessary portion is pressed against the substrate. There is a belt masking method in which plating is performed by spraying a plating solution from an opening of a mask. The tolerance of the width of the plating layer to be formed is about ± 0.1 mm for the tape masking method and about ± 0.2 mm for the belt masking method. In either method, partial plating with higher accuracy than the liquid level control method is possible. Is possible. However, it is difficult to accurately mask a substrate processed into a complicated shape, and these methods cannot be used. In addition, with the recent miniaturization of contact parts, the width of the plating unnecessary portion to be masked has been reduced to, for example, 1 mm or less, and it is difficult to mask such a narrow portion with a tape or belt-like mask. It is.

  As a method capable of accurately masking even a narrow portion as described above, a method of forming a resist mask that covers a plating unnecessary portion by ink jet printing has been proposed (for example, see Patent Document 1). Patent Document 1 discloses that by forming a resist mask by ink jet printing, it is possible to accurately mask even a narrow portion of about 1 mm in width.

  However, in the method disclosed in Patent Document 1, the low wettability region for preventing the solder rise is provided only on one surface in the circumferential direction of the longitudinal portion of the substrate. There is a problem that cannot be obtained. In order to sufficiently exhibit the effect of preventing the solder from rising, it is required to accurately perform partial plating over the entire circumference in the circumferential direction of the longitudinal portion of the substrate. However, in the method disclosed in Patent Document 1, the resist solution is applied to the substrate. Since the resist mask is formed by discharging toward the substrate, it is necessary to provide a plurality of discharge portions around the substrate, and there is a problem that the apparatus becomes large and complicated. In addition, in the case of a substrate having a complicated shape, it is difficult to uniformly apply the resist solution over the entire circumference in the circumferential direction of the longitudinal portion of the substrate.

  As a technique for forming a resist layer on the entire surface of a substrate, it has been proposed to form a resist layer by electrodeposition coating (see, for example, Patent Document 2). However, in the method disclosed in Patent Document 2, after a resist layer is formed by electrodeposition coating on the entire surface of the substrate, a part of the resist layer formed on one surface used as a bonding surface is removed by exposure and development. The exposed portion of the bonding surface is plated. At the time of plating, the other surface of the substrate is not exposed because it is entirely exposed with the resist layer. That is, the invention according to Patent Document 2 was made to perform partial plating on one surface serving as a bonding surface of a substrate, and a method for performing partial plating over the entire circumference in the circumferential direction of the longitudinal portion of the substrate. This is not disclosed in Patent Document 2.

  In another prior art, a method of forming the above-described high wettability region and low wettability region without depending on partial plating has been proposed (for example, see Patent Document 3). In the technique disclosed in Patent Document 3, a nickel plating layer and a gold plating layer are sequentially formed on the entire surface of the longitudinal portion of the substrate, and then a predetermined region is irradiated with laser light to remove a part of the gold plating layer. Thus, the low wettability region is formed by the nickel plating layer exposed over the entire circumference in the circumferential direction of the longitudinal portion, and the high wettability region is formed by the remaining gold plating layer.

  However, in the technique disclosed in Patent Document 3, in order to irradiate laser light over the entire circumference of the longitudinal portion of the base, a plurality of laser light sources are provided around the base, or a plurality of bases are connected. It is necessary to change the device configuration, such as folding the support frame into an S shape and transporting it, and irradiating laser light at two portions where the support frame is bent. . Further, in the technique disclosed in Patent Document 3, the gold plating layer removed from the surface of the nickel plating layer may be scattered and deposited on the peripheral portion, and may contaminate other portions.

  Further, in the technique disclosed in Patent Document 3, since the gold plating layer is directly evaporated and removed by heating by laser light irradiation, the base body is damaged by heating, and the spring characteristics, mechanical strength, etc. of the produced contact parts are reduced. There is also a problem that it falls. Such a decrease in mechanical strength becomes a problem particularly in contact parts of electronic parts that are repeatedly inserted and removed, such as connectors. In addition, when removing the gold plating layer, heat is applied to the underlying nickel plating layer, so that the nickel plating layer is easily peeled off from the surface of the substrate, and long-term as an electronic component. Reliability is also reduced. In addition, as disclosed in Patent Document 3, removing the unnecessary gold plating layer after forming the gold plating layer on the entire surface of the nickel plating layer causes a significant increase in manufacturing cost. It is not practical as a manufacturing method of contact parts.

  Moreover, since it takes time to remove the gold plating layer by laser irradiation, there is a problem that productivity is poor. As a method for shortening the laser beam irradiation time, the technique disclosed in Patent Document 3 leaves a part of the gold plating layer on the surface of the nickel plating layer to be a low wettability region, and is a mixed layer of nickel and gold. It is proposed to form a low wettability region. However, when the low wettability region is formed with a mixed layer of nickel and gold, the effect of preventing solder rise is lower than when the low wettability region is formed with a single nickel layer. Invite.

JP 2004-43852 A (page 3-4, FIG. 1) JP-A-6-173076 (page 3-4) JP 2004-277837 (page 5-7, Fig. 2-4)

  SUMMARY OF THE INVENTION An object of the present invention is to provide a surface treatment method capable of plating a desired portion without causing damage due to heating even on a substrate processed into a complicated shape, and a method for producing an electronic component using the same. Is to provide.

The present invention relates to a surface treatment method for a substrate having a longitudinal portion, the resist layer forming step of forming a resist layer by electrodeposition coating over the entire surface of the longitudinal portion of the substrate, and the substrate and the substrate facing each other And irradiating at least a part of the formed resist layer by irradiating light from at least two directions with respect to the longitudinal portion of the substrate while relatively displacing the two or more light sources provided in such a manner. An exposure step of exposing the entire length of the longitudinal portion of the substrate in the circumferential direction, a development step of developing the exposed resist layer to form a resist pattern, and a resist layer of the longitudinal portion of the substrate. And a plating step of plating a portion that has not been plated.

According to the present invention, the longitudinal portion of the substrate is composed of a low wettability metal layer containing at least a low wettability metal whose surface has low wettability with respect to the solder. A high wettability metal layer containing a highly wettable metal with high wettability with respect to solder is formed by plating on a portion not covered with solder, and after the plating step, a resist removal step of removing the remaining resist layer is performed. It is further characterized by including.
Further, the present invention includes a solder joint portion and a pair of longitudinal portions extending substantially parallel to each other and extending from the solder joint portion, and a connector fitting portion is constituted by an end portion of the longitudinal portion. A resist layer forming step in which the entire surface of the substrate has a low wettability metal layer having low wettability with respect to solder, and a resist layer is formed by electrodeposition coating over the entire surface of the longitudinal portion of the substrate;
A low wettability region excluding the connector fitting portion and the solder joint portion of the formed resist layer is exposed while relatively displacing the base and two or more light sources provided to face each other with the base interposed therebetween. An exposure step of exposing the low-wettability region of the longitudinal portion of the substrate over the entire circumference in the circumferential direction, and development for developing the exposed resist layer to form a resist pattern in the low-wettability region. And a plating step of plating a highly wettable metal having high wettability with respect to solder on a portion of the base portion not covered with the resist layer.

  According to the present invention, the longitudinal portion of the substrate is composed of a highly wettable metal layer containing at least a highly wettable metal whose surface has high wettability with respect to the solder. A low wettability metal layer containing a low wettability metal with low wettability to solder is formed by plating on a portion not covered with solder, and after the plating step, a resist removal step of removing the remaining resist layer is performed. It is further characterized by including.

  Further, the present invention is characterized in that the low wettability metal includes one or more selected from nickel, cobalt, tungsten and iron.

  In the present invention, the highly wettable metal is gold, gold-nickel alloy, gold-cobalt alloy, gold-nickel-cobalt alloy, gold-silver alloy, silver, copper, palladium, palladium-nickel alloy, rhodium, ruthenium, 1 selected from tin, tin-zinc alloy, tin-silver alloy, tin-copper alloy, tin-bismuth alloy, tin-lead alloy, and alloy of tin and at least two of zinc, silver, copper and bismuth It contains a seed or two or more kinds.

  Moreover, this invention is an electronic component manufacturing method characterized by manufacturing an electronic component using the surface treatment method of the said invention.

  According to the present invention, the electronic component is a connector, and the contact component of the connector is formed by the surface treatment method of the present invention.

  According to the present invention, a resist layer is formed by electrodeposition coating on the entire surface of the longitudinal portion of the substrate having the longitudinal portion, and at least a part of the formed resist layer is disposed around the longitudinal portion of the substrate. A resist pattern is formed by exposing and developing the entire circumference in the direction, and plating is performed on a portion of the substrate that is not covered with the resist layer (hereinafter referred to as a resist non-covered portion). When exposing the resist layer, the resist layer is exposed over the entire circumference of the longitudinal portion of the substrate, so that after development, a resist pattern is continuously formed over the entire circumference of the longitudinal portion of the substrate. Can do. Therefore, it is possible to apply plating to a desired portion of the longitudinal portion of the substrate processed into a complex shape over the entire circumference. In addition, since only the necessary part can be plated in this way, the manufacturing cost is greatly reduced compared with the case where the plating layer of the unnecessary part is removed after the entire surface of the longitudinal part of the substrate is plated. Can be reduced. Furthermore, since heat is not applied to the substrate as in the case of removing unnecessary portions of the plating layer by laser light irradiation, it is possible to suppress degradation of the spring characteristics and mechanical strength of the substrate and peeling of the substrate surface layer. Can do.

Also, in exposing the resist layer, exposure is preferred to irradiate light from at least two directions relative to the longitudinal shaped portion of the substrate, the two or more light sources provided so as to face each other across the substrate It is more preferable to carry out. By performing exposure in this way, the resist layer can be easily exposed over the entire circumference in the circumferential direction of the longitudinal portion. Moreover, since such exposure can be performed using an exposure apparatus having a simple structure, the manufacturing apparatus can be reduced in size and simplified as compared with the case where a resist mask is formed by ink jet printing.

Also, after performing plating resist non-covered portion of the elongated portion of the substrate, removing the resist layer remaining. When the surface of the longitudinal part of the substrate is composed of a low wettability metal layer and a high wettability metal layer is formed on the resist uncoated part of the longitudinal part, the surface of the longitudinal part is removed after removing the resist layer. The low wettability metal layer that constitutes is exposed. In addition, when the surface of the longitudinal portion of the substrate is composed of a highly wettable metal layer and a low wettability metal layer is formed on the resist non-covered portion of the longitudinal portion, the longitudinal portion is removed after removing the resist layer. The highly wettable metal layer constituting the surface is exposed. Therefore, a low wettability region with low wettability with respect to solder and a high wettability region with high wettability with respect to solder are formed side by side in the longitudinal direction of the longitudinal portion over the entire circumference of the longitudinal portion of the substrate. Can do.

  Moreover, according to this invention, it is preferable to use 1 type, or 2 or more types chosen from nickel, cobalt, tungsten, and iron as a low wettability metal.

  According to the present invention, the highly wettable metal may be gold, gold-nickel alloy, gold-cobalt alloy, gold-nickel-cobalt alloy, gold-silver alloy, silver, copper, palladium, palladium-nickel alloy, rhodium, Selected from ruthenium, tin, tin-zinc alloy, tin-silver alloy, tin-copper alloy, tin-bismuth alloy, tin-lead alloy, and alloy of tin and at least two of zinc, silver, copper and bismuth It is preferable to use 1 type, or 2 or more types. These metals have excellent wettability with respect to solder, electrical contact resistance is lower than other metals, and excellent corrosion resistance. Therefore, by using these metals, a low contact resistance region having low electrical contact resistance and excellent corrosion resistance can be formed together with a high wettability region.

  According to the invention, the electronic component is manufactured using the surface treatment method of the invention. By using the surface treatment method of the present invention, it is possible to plate a desired portion of the longitudinal portion over the entire circumference in the circumferential direction even on a substrate processed into a complicated shape as described above. Therefore, it is possible to easily manufacture an electronic component having a desired shape and having a desired portion plated.

  According to the invention, the contact part of the connector is formed by the surface treatment method of the invention. This makes it possible to produce a contact component having a low wettability region and a high wettability region without reducing spring characteristics, mechanical strength, and the like by heating with laser light. By manufacturing a connector using such contact parts, it is possible to obtain a connector that suppresses soldering to the connector fitting portion during soldering, has no defects due to soldering, and has excellent durability.

  FIG. 1 is a diagram showing a simplified configuration of a connector pin 1 which is an example of a contact component provided in an electronic component manufactured by the electronic component manufacturing method of the present invention. FIG. 1A is a perspective view showing the connector pin 1 as viewed from the longitudinal portion 6 side. FIG.1 (b) is sectional drawing which shows the connector fitting part 5 of the connector pin 1 shown to Fig.1 (a) seeing from the cut surface line II. FIG.1 (c) is sectional drawing which shows the low wettability area | region 3 of the connector pin 1 shown to Fig.1 (a) seeing from the cut surface line II-II. FIG.1 (d) is sectional drawing which shows the solder joint part 4 of the connector pin 1 shown to Fig.1 (a) seeing from the cut surface line III-III. Since the two connector fitting parts 5 have the same configuration, only one of the two connector fitting parts 5 is shown in FIG. Further, since the two low wettability regions 3 have the same configuration, only one of the two low wettability regions 3 is shown in FIG.

  The connector pin 1 includes a solder joint portion 4 and a pair of longitudinal portions 6 that extend from the solder joint portion 4 so as to be substantially parallel to each other. The connector fitting portion 5 is constituted by the end portion of the longitudinal portion 6. In the present embodiment, each of the two longitudinal portions 6 has a substantially prismatic shape.

  The connector pin 1 is soldered by a solder joint portion 4 and mounted on a substrate (not shown), and the connector pin 1 is used by being fitted to another connector (not shown) which is paired by a connector fitting portion 5. Another pair of connectors fitted to the connector fitting portion 5 is mounted on a substrate different from the substrate on which the connector pins 1 are mounted. By fitting with another pair of connectors at the connector fitting portion 5, the board on which the connector pins 1 are mounted and the board on which another pair of connectors are mounted can be electrically connected. .

  The solder joint portion 4 has a high wettability region 2b excellent in solder wettability. In the present embodiment, the entire solder joint portion 4 is formed as the high wettability region 2b. The connector fitting portion 5 has a low contact resistance region 2a having a low contact resistance of, for example, 1 to 10 mΩ (contact load 25 g) and excellent corrosion resistance. In the present embodiment, the entire connector fitting portion 5 is formed as the low contact resistance region 2a. A low wettability region 3 that is inferior in wettability with solder is provided between the solder joint portion 4 and the connector fitting portion 5. In the present embodiment, the low wettability region 3 is formed in the middle portion in the longitudinal direction of the two longitudinal portions 6 over the entire circumference in the circumferential direction of the longitudinal portion 6. Further, a high wettability region 2 b is formed continuously from the solder joint portion 4 at the base end portion connected to the solder joint portion 4 of the longitudinal portion 6. That is, in the present embodiment, the high wettability region 2b, the low wettability region 3 and the low contact resistance region 2a are formed side by side in the longitudinal direction of the longitudinal portion 6 of the connector pin 1 in this order.

  Solder to the connector fitting portion 5 when soldering to the solder joint portion 4 by providing the low wettability region 3 between the solder joint portion 4 and the connector fitting portion 5 as in this embodiment. The rise can be prevented. Specifically, when soldering to the solder joint portion 4, the molten solder flows from the solder joint portion 4 toward the connector fitting portion 5, but between the solder joint portion 4 and the connector fitting portion 5. Is provided with the low wettability region 3, the flow in the direction of the connector fitting portion 5 is prevented by the low wettability region 3 and does not reach the connector fitting portion 5. Therefore, it is possible to prevent solder from rising from the solder joint portion 4 to the connector fitting portion 5. In particular, in the present embodiment, the low wettability region 3 is formed over the entire circumference in the circumferential direction of the longitudinal portion 6, so that it is possible to reliably prevent the solder from rising.

  The connector pin 1 includes a base 14, a high wettability metal layer 13 b and a low contact resistance metal layer 13 a formed on the surface of the base 14. The base 14 includes a base body 11 and a low wettability metal layer 12 formed on the surface of the base body 11. The low wettability metal layer 12 contains a low wettability metal having low wettability with solder. The high wettability metal layer 13b contains a high wettability metal having high wettability with the solder. The low contact resistance metal layer 13a contains a low contact resistance metal having a low contact resistance of, for example, 1 to 10 mΩ (contact load 25 g) and excellent corrosion resistance.

  The low wettability metal layer 12 is formed on the entire surface of the base body 11 and constitutes a surface layer of the base body 14. In the solder joint portion 4, a highly wettable metal layer 13 b is formed on the surface of the base 14. The portion where the high wettability metal layer 13b is formed constitutes the high wettability region 2b. In the connector fitting portion 5, a low contact resistance metal layer 13 a is formed on the surface of the base 14. The portion where the low contact resistance metal layer 13a is formed constitutes the low contact resistance region 2a. In the low wettability region 3, the low contact resistance metal layer 13a and the high wettability metal layer 13b are not formed on the surface of the base 14, and the low wettability metal layer 12 is exposed. The portion where the low wettability metal layer 12 is exposed constitutes the low wettability region 3.

  In the present embodiment, the low contact resistance metal layer 13a and the high wettability metal layer 13b are formed of the same material. The low contact resistance metal layer 13a and the high wettability metal layer 13b may be formed of different materials, but are preferably formed of the same material as in this embodiment. Accordingly, the low contact resistance metal layer 13a and the high wettability metal layer 13b can be formed at the same time in the plating process described later, so that the manufacturing process can be simplified.

  The method for manufacturing an electronic component of the present invention for manufacturing an electronic component including a contact component such as the connector pin 1 shown in FIG. 1 uses the surface treatment method of the present invention. explain. The surface treatment method of the present invention includes at least a resist layer forming step, an exposure step, a development step, and a plating step. The surface treatment method according to one embodiment of the present invention includes a base plating step, a resist layer forming step, an exposure step, a development step, a plating step, and a resist removal step.

[Under plating process]
FIG. 2 is a view showing a state in which the low wettability metal layer 12 is formed on the surface of the base body 11. 2A is a side view showing the strip 9 as seen from one side in the thickness direction, and FIG. 2B is a perspective view showing the base 14 as seen from the longitudinal portion 7 side. In FIG. 2B, one of the bases 14 included in the strip 9 shown in FIG. In the surface treatment method of this embodiment, first, the base body 11 is plated, and the low wettability metal layer 12 is formed over the entire surface of the base body 11. As a result, a base body 14 composed of the base body 11 and the low wettability metal layer 12 is formed.

  In the present embodiment, in the state of the strip 9a in which the plurality of base bodies 11 are supported on the support frame 10 via the base support portion 8, the longitudinal portion 6 is in a direction perpendicular to the thickness direction of the base body 11. Surface treatment is continuously performed while transporting in the direction of the arrow 16 which is a direction perpendicular to the longitudinal direction. The strip material 9a includes a plurality of base body bodies 11, base body support portions 8a, and a support frame 10. In this embodiment, the base body 11 is formed integrally with the base support portion 8a and the support frame 10, and the low wettability metal layer 12 is formed on the base body 11 and the base support portion 8a. The substrate 14 on which the low wettability metal layer 12 is formed is subjected to the next resist formation step in the state of the strip 9 connected to the support frame 10 via the substrate support portion 8.

  In the present embodiment, the base 14 is connected to the first surface 14a and the first surface 14a, which is a surface parallel to the paper surface of FIG. A second surface 14b that is a surface that is on the right side of the first surface 14a toward the paper surface of FIG. 2A, and a surface parallel to the paper surface of FIG. A third surface 14c that is the other surface, a fourth side surface 14d that is a surface that is continuous with the first surface 14a and that is on the left side of the first surface 14a toward the paper surface of FIG. It has the 5th surface 14e and the 6th surface 14f which are the surfaces where two longitudinal parts 7 oppose.

  As a material constituting the substrate body 11, a known conductive material can be used. Among them, copper, copper-nickel alloy, titanium-copper alloy, phosphor bronze, copper alloy such as brass, nickel-iron alloy, etc. Preferably used. These materials are processed into a desired shape by punching or the like and used as the base body 11. The shape of the base body 11 is appropriately selected according to the shape of the connector pin 1 to be manufactured. The support frame 10 and the base support portion 8 can be integrally formed with the base body 11 by punching or the like.

  The low wettability metal layer 12 is formed of, for example, a nickel plating layer. The low wettability metal layer 12 is not limited to this, and any metal containing a low wettability metal having low wettability with respect to solder may be used. As the low wettability metal, it is preferable to use a single metal or an alloy containing one or more selected from nickel, cobalt, tungsten and iron, among which nickel is particularly preferable. Here, the level of wettability with respect to the solder is relative, and the low wettability metal is lower in wettability with respect to the solder than the high wettability metal contained in the high wettability metal layer 13b. It is a metal. Accordingly, the low wettability metal is appropriately selected and used according to the type of metal used as the high wettability metal. The thickness of the low wettability metal layer 12 is, for example, 0.5 to 5 μm.

  Plating of the base body 11 for forming the low wettability metal layer 12 can be performed using, for example, electrolytic plating, chemical plating, or the like. When electrolytic plating is used, the base body 11 can be plated by immersing the base body 11 in a plating bath containing metal ions that form the low wettability metal layer 12 and energizing it. As the plating bath, when nickel plating is performed, for example, a watt bath, a sulfamic acid bath, or the like can be used. Examples of the watt bath include those containing 200 to 300 g / L of nickel sulfate, 30 to 60 g / L of nickel chloride, 20 to 50 g / L of boric acid, and 0.1 to 3 g / L of saccharin. Examples of the sulfamic acid bath include crystalline nickel sulfamate 300 to 450 g / L, boric acid 20 to 50 g / L and surfactant 0.1 to 1 g / L, and nickel chloride 5 to 30 g / L. Examples include those added.

  The sum L of the length of the longitudinal portion 7 of the base 14 formed by forming the low wettability metal layer 12 on the surface of the base body 11 as described above and the length in the longitudinal direction of the base support 8 is, for example, 1 to 20 mm. It is. The shortest distance (hereinafter referred to as the interval) W between the first longitudinal portion 7a and the second longitudinal portion 7b of the base 14 is, for example, 0.5 to 5 mm. The thickness of the base 14, that is, the length S in the direction perpendicular to the longitudinal direction of the longitudinal portion 7 and perpendicular to the transport direction 16 is, for example, 0.1 to 0.3 mm. Moreover, the space | interval (henceforth a pitch) T between the opposing longitudinal parts 7 of the adjacent base | substrate 14 is 0.1-5 mm, for example.

  As described above, since the thickness of the low wettability metal layer 12 is as thin as 0.5 to 5 μm, the length in the longitudinal direction of the portion that becomes the longitudinal portion 7 of the base body 11 and the length in the longitudinal direction of the base support portion 8a. The sum L ′ of the length, the interval W ′ and the thickness S ′ between the portion serving as the first longitudinal portion 7 a and the portion serving as the second longitudinal portion 7 b are respectively the length of the longitudinal portion 7 of the base 14. The sum L of the lengths in the longitudinal direction of the substrate support portion 8, the interval W between the first longitudinal portion 7a and the second longitudinal portion 7b, and the thickness S are substantially equal. Further, the pitch T ′ that is the distance between the opposing longitudinal portions 7 of the adjacent base body 11 is substantially equal to the pitch T in the base 14.

  Next, a resist layer forming step and an exposure step are performed. FIG. 3 is a cross-sectional view showing a simplified state of the substrate 14 in the exposure process. FIG. 3 is a cross-sectional view showing the first longitudinal portion 7a of the base body 14 shown in FIG. 2A as viewed from a cutting plane line IV-IV perpendicular to the transport direction 16, and the base body shown in FIG. The conveyance direction 16 of 14 corresponds to a direction perpendicular to the paper surface of FIG. FIG. 3 shows a case where the resist layer 15 is formed of a negative resist electrodeposition paint described later.

[Resist layer forming step]
In the resist layer forming step, a resist layer 15 is formed by electrodeposition coating over the entire surface of at least the longitudinal portion 7 of the base body 14 in which the low wettability metal layer 12 is formed on the base body 11 described above. . In this embodiment, the resist layer 15 is continuously formed over the entire exposed surface including the entire surface of the longitudinal portion of the substrate 14 and the entire surface of the substrate support 8. By forming the resist layer 15 by electrodeposition coating, the resist layer 15 can be formed with a uniform thickness on the entire surface of the substrate 14 and the entire surface of the substrate support 8. Specifically, the first surface 14a and the thickness direction, which are the surfaces on the one side in the thickness direction of the substrate 14, also with respect to the second surface 14b and the fourth surface 14d of the substrate 14 which are surfaces facing the adjacent substrate 14. It is possible to easily form the resist layer 15 having the same uniform thickness as the third surface 14c which is the other surface. Further, the resist layer 15 having the same uniform thickness as the first surface 14a and the fourth surface 14d is also applied to the fifth surface 14e and the sixth surface 14f, which are the surfaces of the two longitudinal portions 7a and 7b facing each other. Can be formed. Thus, in this embodiment, the resist layer 15 having a uniform thickness can be easily formed over the entire surface of the longitudinal portion 7.

  The thickness d of the resist layer 15 is preferably 3 μm or more and 30 μm or less, and more preferably 5 μm or more and 20 μm or less. The reason for this will be described later. In this embodiment, since the resist layer 15 is formed by electrodeposition coating, the thickness can be easily adjusted, and the resist layer 15 having a thickness within the above range can be easily formed.

  Electrodeposition coating on the substrate 14 is carried out according to a known method, for example, by immersing the substrate 14 in an energization tank filled with an electrodeposition paint and energizing in this state. As the electrodeposition paint, a resist electrodeposition paint that can form a photosensitive coating film as the resist layer 15 is used. As a resist electrodeposition paint, a negative resist electrodeposition paint that can form a coating film in which an exposed part is cured and becomes insoluble or hardly soluble in a developer, and the exposed part is decomposed into a developer. Any of positive resist electrodeposition paints capable of forming a soluble coating film may be used. These resist electrodeposition paints may be either a cation type or an anion type.

  As a negative resist electrodeposition coating, for example, a mixture of an acrylate copolymer and a polyfunctional unsaturated acrylate having a plurality of functional groups such as acryloyl group and methacryloyl group is neutralized with an appropriate neutralizing agent. And those dispersed in water. Examples of the positive resist electrodeposition coating material include those obtained by neutralizing an acrylic acid ester copolymer having a quinonediazide group with a suitable neutralizing agent and dispersing it in water. These resist electrodeposition paints can be adjusted to a cation type or an anion type by introducing an appropriate functional group into a resin such as an acrylic ester copolymer contained therein.

  When an anion type resist electrodeposition coating is used, the substrate 14 is used as an anode, and for example, a carbon plate, a stainless steel plate or the like is used as a cathode. Conversely, when using a cation type resist electrodeposition coating, the substrate 14 is used as a cathode, and a carbon plate, a stainless steel plate or the like is used as an anode. Which of the cation type and the anion type resist electrodeposition paint is used is appropriately selected according to the materials constituting the substrate body 11 and the low wettability metal layer 12. The thickness d of the resist layer 15 to be formed can be easily adjusted by the applied voltage applied between the electrodes and the voltage application time. Electrodeposition conditions include the thickness d of the resist layer 15 to be formed, the composition of the resist electrodeposition paint used, the type of metal constituting the low-wettable metal layer 12 that is the surface layer of the substrate 14, It can be appropriately selected from a wide range according to various conditions such as size and shape. For example, the liquid temperature of the resist electrodeposition coating is about 10 to 50 ° C., the applied voltage is about 10 to 250 V, and the voltage application time is about 5 seconds to 5 minutes. is there.

[Exposure process]
In the exposure step, at least a part of the resist layer 15 formed on the longitudinal portion 7 of the substrate 14 is exposed over the entire circumference in the circumferential direction of the longitudinal portion 7. By exposing the resist layer 15 over the entire circumference in the circumferential direction of the longitudinal portion 7 in this way, even if the substrate 14 has a complicated shape as shown in FIG. As shown in FIG. 3, the resist pattern 16 can be formed over the entire circumference in the circumferential direction of the longitudinal portion 7 of the substrate 14. Therefore, in the plating step described later, partial plating can be performed with high accuracy over the entire circumference of the longitudinal portion 7 of the base body 14.

  In this embodiment, the resist layer 15 is exposed to a resist layer formed in a predetermined portion 23 (hereinafter referred to as a low wettability region formation scheduled portion) to form the low wettability region 3 shown in FIG. 15a is performed so that it remains after development. For example, when the resist layer 15 is formed of a negative resist electrodeposition paint, the resist layer 15 formed on the low wettability region formation planned portion 23 of the longitudinal portion 7 of the base 14 is formed as shown in FIG. Then, the entire length of the longitudinal portion 7 is exposed and cured. When the resist layer 15 is formed of a positive resist electrodeposition paint, the resist layer 15b formed on the portion 22 of the longitudinal portion 7 of the substrate 14 excluding the low wettability region formation planned portion 23 is exposed. To be soluble in the developer.

  Specifically, the exposure to the resist layer 15 can be performed by irradiating the longitudinal portion 7 of the substrate 14 with light from at least two directions. In this embodiment, as shown in FIG. 3, the base 14 is transported from the front side to the back side in FIG. 3 by using two light sources 18 and 19 provided to face each other with the base 14 interposed therebetween. However, exposure is performed by irradiating light from two directions indicated by the arrow 20 and the arrow 21. In the present embodiment, light sources 18 and 19 that can irradiate diffused light are used.

  Light emitted from the light sources 18 and 19 is applied to the resist layer 15 on the surface of the substrate 14 through the opening of the exposure mask 17. In this exposure, when the base body 14 is positioned on the upstream side in the transport direction of the base body 14 with respect to the virtual plane connecting the first light source 18 and the second light source 19, the surface on the downstream side of the base body 14 in the transport direction, specifically the longitudinal direction. Light is irradiated to the fourth surface 14d and the sixth surface 14f of the shaped portion 7. When the base body 14 is transported and positioned in the vicinity of a virtual plane connecting the first light source 18 and the second light source 19, the first surface 14 a and the third surface 14 of the longitudinal portion 7 that are both surface portions in the thickness direction of the base body 14. Light is irradiated to the surface 14c. When the base 14 is further transported and is located downstream of the base 14 in the transport direction with respect to the virtual plane connecting the first light source 18 and the second light source 19, the surface upstream of the base 14 in the transport direction, specifically the longitudinal direction The second surface 14b and the fifth surface 14e of the shaped portion 7 are irradiated with light. Thus, in this embodiment, since the exposure is performed while relatively displacing the base body 14 and two or more light sources, specifically, the two light sources 18 and 19 provided at intervals, the resist layer 15 is exposed. Can be easily exposed over the entire circumference of the longitudinal portion 7 in the circumferential direction. In addition, since such exposure can be performed using an exposure apparatus having a simple structure, the manufacturing apparatus can be reduced in size and simplified as compared with the case where a resist mask is formed by ink jet printing.

  When the resist layer 15 is formed of a positive resist electrodeposition coating, it is necessary to expose the entire portion 22 except the low wettability region formation scheduled portion 23. In this embodiment, the solder joint portion 4 and Among the portions to be formed, the resist layer 15 formed on the connecting portion 4a connecting the longitudinal portions 7 shown in FIG. 2 can also be exposed over the entire circumference of the connecting portion 4a. That is, the resist layer 15 formed on the surface facing the support frame 10 of the connecting portion 4a and the surface facing the space formed by the long portions 7 can be reliably exposed.

  In order to improve the exposure accuracy with respect to the resist layer 15, the thickness d of the resist layer 15 is preferably 3 μm or more and 30 μm or less, and more preferably 5 μm or more and 20 μm or less. By forming the resist layer 15 so that the thickness d is within the above range, not only the first surface 14a and the third surface 14c of the substrate 14, but also the second surface 14b and the fourth surface 14d, and the longitudinal portion The fifth surface 14e and the sixth surface 14f, which are the surfaces facing each other, can be easily exposed with high accuracy.

  In particular, as in the present embodiment, when the substrate 14 is transported to the resist layer 15 and exposure is performed by irradiating light from two light sources 18 and 19 facing each other with the substrate 14 interposed therebetween, It is preferable that the thickness d of the resist layer 15 be in the above range. Thus, the formed resist layer 15 can be reliably exposed over the entire circumference in the circumferential direction of the longitudinal portion 7. Therefore, after development, the resist pattern 16 can be accurately formed over the entire circumference of the longitudinal portion 7 of the substrate 14.

  If the thickness d of the resist layer 15 exceeds 30 μm, the exposure accuracy may decrease, and the accuracy of the resist pattern 16 may decrease. Further, in the case where exposure is performed by irradiating light from two light sources 18 and 19 facing each other with the base 14 interposed therebetween as in the present embodiment, the surface of the base 14 that does not face the light sources 18 and 19 is used. Exposure to the resist layer 15 formed on the second surface 14b and the fourth surface 14d and the fifth surface 14e and the sixth surface 14f, which are the opposing surfaces of the longitudinal portions 7, becomes insufficient, and the resist layer 15 is elongated. There is a possibility that exposure cannot be performed over the entire circumference of the shaped portion 7. When the thickness of the resist layer 15 is less than 3 μm, the resist layer 15 to be left in the development step described later, for example, in the case of the resist layer 15 formed of a negative resist electrodeposition paint, the exposed portion of the resist There is a possibility that the layer 15 may be peeled off, and there is a possibility that accurate partial plating cannot be performed in the plating process described later.

  As an exposure apparatus suitably used for exposure of the resist layer 15 according to this embodiment, for example, an exposure apparatus 24 shown in FIG. FIG. 4 is a side view showing a simplified configuration of the exposure apparatus 24 that is preferably used for exposure of the resist layer 15. FIG. 5 is a perspective view showing the first mask portion 25 provided in the exposure apparatus 24 as viewed from the vertically upward direction. In FIG. 4, the resist layer 15 shown in FIG. 3 is not shown because it is difficult to understand because the drawings are complicated. The exposure apparatus 24 includes a first mask unit 25, a second mask unit 26, a first light source 18, and a second light source 19.

  The first mask portion 25 includes a first upper mask 27, a first lower mask 28 provided vertically below the first upper mask 27, a first upper support 29 that supports the first upper mask 27, 1 includes a first lower support 30 that supports the lower mask 28, and a first support base 31 that supports the first upper support 29 and the first lower support 30. The first upper support 29 and the first lower support 30 are supported by the first support base 31 so as to be movable in the vertical direction which is the vertical direction toward the paper surface of FIG.

  The second mask portion 26 has the same configuration as the first mask portion 25, and includes a second upper mask 32, a second lower mask 33 provided in the vertical direction of the second upper mask 32, and a second upper mask. 32, a second upper support 34 that supports 32, a second lower support 35 that supports the second lower mask 33, and a second support that supports the second upper support 34 and the second lower support 35. And a substrate 36. The second upper support 34 and the second lower support 35 are supported by the second support base 36 independently of each other so as to be movable in the vertical direction that is the vertical direction toward the plane of FIG.

  The first upper mask 27, the first lower mask 28, the second upper mask 32, and the second lower mask 33 function as the exposure mask 17 shown in FIG. The first upper mask 27, the first lower mask 28, the second upper mask 32, and the second lower mask 33 are members independent of each other, and the first upper support 29, the first that supports these masks, and the first. By moving the lower support 30, the second upper support 34, or the second lower support 35, they can be moved in the vertical direction that is the vertical direction toward the paper surface of FIG. 4. Thus, the distance between the first upper mask 27 and the first lower mask 28, that is, the opening formed by the first upper mask 27 and the first lower mask 28 (hereinafter referred to as the first mask opening). 37, and a distance between the second upper mask 32 and the second lower mask 33, that is, an opening formed by the second upper mask 32 and the second lower mask 33 (hereinafter referred to as a second mask opening). The width D2 of 38) can be adjusted respectively.

  The first mask portion 25 and the second mask portion 26 are such that the first upper mask 27 and the second upper mask 32 face each other, and the first lower mask 28 and the second lower mask 33 face each other. Provided at intervals. At the time of exposure, the base body 14 opens an opening 39 (hereinafter referred to as an inter-mask opening) 39 formed by the first mask portion 25 and the second mask portion 26 from the front side to the back side in FIG. Be transported.

  In the exposure apparatus 24 shown in FIG. 4, the first lower mask 28 has a concave curved surface at the portion facing the vertical lower end of the surface facing the second lower mask 33, and the vertical lower end is vertical. The width is narrower than the upper end. Similarly, the second lower mask 33 has a concave curved surface at the surface facing the first lower mask 28, and the vertical lower end is wider than the vertical upper end. Is narrower. For this reason, the space | interval of the 1st lower mask 28 and the 2nd lower mask 33 is large in the vertically lower side edge part compared with the vertically upward side edge part. When the base 14 is connected to the support frame 10 and transported, the widened portion is used as a portion through which the base transport belt 40 that supports and transports the support frame 10 passes.

  By providing a portion with such a wide interval, and using this portion as a passage portion of the substrate transport belt 40, the distance between the first mask portion 25 and the substrate 14 and the first distance without interfering with the movement of the substrate 14 can be obtained. 2 The distance between the mask portion 26 and the base 14 can be reduced. As a result, the exposure accuracy for the resist layer 15 formed on the substrate 14 can be improved, so that the resist pattern 16 can be formed with high accuracy. The minimum value of the width of the inter-mask opening 39, that is, the distance between the first mask portion 25 and the second mask portion 26 (hereinafter, this value is referred to as the width of the inter-mask opening 39) D3 is It is appropriately selected according to the thickness S.

The first light source 18 faces the first upper mask 27 and the first lower mask 28 and is provided so as to be able to irradiate light toward the first mask opening 37. The second light source 19 faces the second upper mask 32 and the second lower mask 33 and is provided so as to be able to irradiate light toward the second mask opening 38. As the exposure light, for example, ultraviolet rays having a wavelength of 150 to 400 nm can be used. As the 1st and 2nd light sources 18 and 19 which can radiate | emit such an ultraviolet-ray, a high pressure mercury lamp, a metal halide lamp etc. can be used, for example. The amount of exposure light applied to the resist layer 15 is, for example, 50 to 1000 mJ / cm ² . The wavelength and irradiation amount of the exposure light are appropriately selected according to the photosensitivity of the resist electrodeposition coating material that forms the resist layer 15.

  The exposure device 24 irradiates light from the first and second light sources 18 and 19 toward the first and second mask openings 37 and 38, so that the first of the resist layers 15 formed on the substrate 14. Further, the resist layer 15 corresponding to the second mask openings 37 and 38 can be exposed over the entire circumference of the longitudinal portion 7 as shown in FIG. In the exposure apparatus 24, the width of the exposed portion in the longitudinal direction of the longitudinal portion 7 of the resist layer 15 is adjusted by adjusting the width D1 of the first mask opening 37 and the width D2 of the second mask opening 38. Can be adjusted easily.

  In this embodiment, the exposure is performed using the two light sources 18 and 19, but the exposure may be performed using three or more light sources. In this case, the light sources are arranged in order in the transport direction of the base 14 so as to face each other with the base 14 interposed therebetween. For example, when four light sources are used, two light sources are provided side by side in the transport direction of the base body 14 on the opposite side with respect to the base body 14. In this way, by providing a plurality of light sources arranged on the opposite side with respect to the base 14 in the transport direction of the base 14, the resist layer 15 can be more reliably exposed over the entire circumference of the longitudinal portion 7.

  In this embodiment, the exposure is performed while the substrate 14 is being transported. However, the substrate 14 may be fixed and the exposure may be performed while the exposure apparatus including the light sources 18 and 19 is transported.

[Development process]
FIG. 6 is a diagram showing a state after development of the resist layer 15. 6A is a side view showing the base body 14 as seen from one side in the thickness direction, and FIG. 6B is a perspective view showing the base body 14 as seen from the longitudinal portion 7 side. FIG. 6B shows an enlarged view of one of the base bodies 14 shown in FIG. In the development step, the exposed resist layer 15 is developed as described above. As a result, the resist layer 15 formed in the portion 22 excluding the low wettability region formation planned portion 23 is removed, and the resist pattern 16 in which the resist layer 15 exists only in the low wettability region formation planned portion 23 is formed. In the present embodiment, as described above, the resist layer 15 of the low wettability region formation scheduled portion 23 is exposed over the entire circumference of the longitudinal portion 7, so that the resist is coated over the entire circumference of the longitudinal portion 7 of the substrate 14. A pattern 16 can be formed.

  A known developer can be used for developing the resist layer 15. For example, when the resist layer 15 is formed of a negative resist electrodeposition coating, 0.5 to 20% by weight of an organic acid such as lactic acid, formic acid, acetic acid or citric acid and 0.5 to 20% by weight of a surfactant are used. An aqueous solution containing can be used. Further, when the resist layer 15 is formed of a positive resist electrodeposition coating, a 5 wt% sodium metasilicate aqueous solution, a 1-2 wt% sodium hydroxide aqueous solution, or the like can be used.

[Plating process]
In the plating step, the base 14 on which the resist pattern 16 is formed is plated. As a result, plating is applied to the resist uncovered portion 22 of the substrate 14, that is, the surface of the longitudinal portion 7 that is not covered with the resist layer 15 and the surface of the portion that becomes the solder joint portion 4, as shown in FIG. Thus, the low contact resistance metal layer 13a and the high wettability metal layer 13b are formed. The portion where the low contact resistance metal layer 13a is formed becomes the low contact resistance region 2a, and the portion where the high wettability metal layer 13b is formed becomes the high wettability region 2b.

  The low contact resistance metal layer 13a and the high wettability metal layer 13b thus formed are made of the same material. In this way, the low contact resistance metal layer 13a and the high wettability metal layer 13b are formed of the same material, thereby forming the low contact resistance metal layer 13a and the high wettability metal layer 13b simultaneously by one plating. Therefore, the manufacturing process can be simplified as compared with the case where the low contact resistance metal layer 13a and the high wettability metal layer 13b are formed of different materials.

  When the low contact resistance metal layer 13a and the high wettability metal layer 13b are formed of the same material, the metal layer that becomes the low contact resistance metal layer 13a and the high wettability metal layer 13b is formed of, for example, a gold plating layer. . The metal layer that becomes the low contact resistance metal layer 13a and the high wettability metal layer 13b is not limited to this, and any metal layer that has both the properties of the low contact resistance metal and the high wettability metal can be used. It may be made of any metal.

  As a metal forming a metal layer to be the low contact resistance metal layer 13a and the high wettability metal layer 13b, that is, a metal having low contact resistance, excellent corrosion resistance, and excellent wettability with solder, gold, gold-nickel alloy , Gold-cobalt alloy, gold-nickel-cobalt alloy, gold-silver alloy, silver, copper, palladium, palladium-nickel alloy, rhodium, ruthenium, tin, tin-zinc alloy, tin-silver alloy, tin-copper alloy, It is preferable to use one or two or more selected from tin-bismuth alloys, tin-lead alloys, and alloys of tin and zinc, at least two of silver, copper, and bismuth. Among these, gold, gold -Nickel alloy, gold-cobalt alloy, palladium-nickel alloy, tin-silver alloy and tin-copper alloy are preferable, and gold is particularly preferable.

  Plating of the substrate 14 for forming the low contact resistance metal layer 13a and the high wettability metal layer 13b can be performed using, for example, electrolytic plating, chemical plating, or the like. When electrolytic plating is used, the substrate 14 is plated by immersing the substrate 14 on which the resist pattern 16 is formed in a plating bath containing metal ions forming the low contact resistance metal layer 13a and the high wettability metal layer 13b. It can be done by doing. As the plating bath, when performing gold plating, a known acidic, neutral or alkaline gold plating bath can be used, for example, an acidic gold plating bath containing potassium gold cyanide, citric acid, or cobalt salt. And neutral gold plating bath containing potassium gold cyanide and sodium phosphate. In addition, when performing tin-copper alloy plating, a known acidic, neutral or alkaline tin-copper alloy plating bath can be used, for example, an acid containing tin methanesulfonate, copper sulfate, and methanesulfonic acid. And a tin-copper alloy plating bath.

  As described above, the metal constituting the low contact resistance metal layer 13a and the metal constituting the high wettability metal layer 13b are preferably the same, but they may be different. In this case, the metal constituting the low contact resistance metal layer 13a and the high wettability metal layer 13b is exemplified as the metal forming the metal layer to be the low contact resistance metal layer 13a and the high wettability metal layer 13b. Each can be selected from. The material which comprises the low contact resistance metal layer 13a is not limited to this, What is necessary is just a metal with low contact resistance and excellent corrosion resistance. Moreover, the material which comprises the highly wettable metal layer 13b is not limited to this, What is necessary is just a metal excellent in the wettability with a solder. When the low contact resistance metal layer 13a and the high wettability metal layer 13b are formed of different materials, for example, a portion of the low wettability metal layer 12 that is predetermined to form the low contact resistance metal layer 13a is plated with a mask. After plating is performed in a state covered with, the high wettability metal layer 13b is formed, the surface of the high wettability region 13b is covered with a plating mask, and plating is performed in this state to form the low contact resistance metal layer 13a.

[Resist removal process]
After plating the resist uncoated portion of the substrate 14 as described above, the remaining resist layer 15 is removed in a resist removing step. As a result, the low wettability metal layer 12 covered with the resist layer 15 is exposed, and the low wettability region 3 shown in FIG. 1 is formed. The removal of the resist layer 15 can be performed, for example, by immersing the base 14 after plating in a resist stripping solution and stripping the resist layer 15. As the resist stripping solution, when the resist layer 15 is formed of a negative resist electrodeposition paint, 0.5 to 20% by weight of an organic acid such as lactic acid, formic acid, acetic acid or citric acid, and a surfactant 0.5 An aqueous solution containing -20% by weight and 0.5-50% by weight of an organic solvent such as benzyl alcohol can be used. Moreover, when forming the resist layer 15 with a positive resist electrodeposition coating material, 5-25 weight% sodium hydroxide aqueous solution etc. can be used.

  After forming the low wettability region 3 in this way, the base 14 and the base support portion 8 are cut at the virtual plane 41 and the base 14 is separated from the support frame 10. Thereby, the connector pin 1 shown in FIG. 1 in which the low wettability region 3 is formed between the solder joint portion 4 and the connector fitting portion 5 is obtained.

  As described above, in this embodiment, in the exposure step, at least a part of the resist layer 15 is exposed over the entire circumference in the circumferential direction of the longitudinal part 7 as shown in FIG. The resist pattern 16 can be formed over the entire circumference in the circumferential direction. Therefore, even on the base 14 processed into a complicated shape, it is possible to plate the desired portion of the longitudinal portion 7 of the base 14 over the entire circumference, so that the connector pin 1 shown in FIG. In addition, the contact component in which the low wettability region 3 is formed over the entire circumference of the longitudinal portion 6 can be easily manufactured.

  Moreover, in the surface treatment method of this embodiment, even if the pitch T, which is the distance between the opposing longitudinal portions 7 of the adjacent base bodies 14, is as narrow as 0.1 to 5 mm as described above, the adjacent base bodies In the second surface 14b and the fourth surface 14d of the base body 14, which are the surfaces facing the 14 long portions 7, it is possible to plate desired portions with high accuracy. Thus, the surface treatment method of the present invention can be suitably used when the pitch T is as narrow as 0.1 to 5 mm.

  Further, in the surface treatment method of this embodiment, the width A1 in the longitudinal direction of the longitudinal portion 6 of the low wettability region 3 shown in FIG. 1 is equal to the longitudinal portion 7 of the resist layer 15 remaining after development shown in FIG. It is substantially equal to the width A3 in the longitudinal direction, and can be easily adjusted by the width of the opening of the exposure mask used in the exposure process. For example, when the resist layer 15 is formed of a negative resist electrodeposition paint, the width A2 of the opening of the exposure mask 17 used in the exposure process shown in FIG. 3, specifically, in the exposure apparatus 24 shown in FIG. By adjusting the width D1 of the first mask opening 37 and the width D2 of the second mask opening 38, the low wettability region 3 having the desired width A1 can be easily formed. Therefore, even in the low wettability region 3 having a width A1 of 100 μm or less, it can be easily formed over the entire circumference of the longitudinal portion 7 of the substrate 14.

  Moreover, in the surface treatment method of this embodiment, since it is possible to perform plating only on a necessary portion of the longitudinal portion 7 of the base body 14, the entire surface of the longitudinal portion 7 is plated to provide the low contact resistance metal layer 13a. And compared with the case where the unnecessary part of this metal layer is removed after forming the metal layer used as the highly wettable metal layer 13b, manufacturing cost can be reduced significantly. In particular, when a gold plating layer is formed as a metal layer that becomes the low contact resistance metal layer 13a and the high wettability metal layer 13b, the manufacturing cost can be significantly reduced.

  Further, since heat is not applied to the base 14 as in the case where an unnecessary portion of the metal layer is removed by laser light irradiation, it is possible to suppress a decrease in spring characteristics, mechanical strength, etc. of the base 14. Further, it is possible to prevent the low wettability metal layer 12 which is the surface layer of the base 14 from being peeled off from the base body 11 by the heat generated when the laser light is irradiated. Therefore, the long-term reliability of electronic parts using contact parts such as connector pins 1 can be improved.

  The surface treatment method of this embodiment is not limited to partial plating for forming a low wettability region on a contact part of a connector, and can be used for partial plating when forming contact parts of various electronic parts. For example, it can be used to form a low wettability region in a lead portion which is a contact part of a lead frame. As described above, in the present embodiment, even the base 14 processed into a complicated shape can be plated on the desired portion of the longitudinal portion 7 over the entire circumference in the circumferential direction. It is possible to easily manufacture an electronic component such as a lead frame in which a desired portion is plated.

  As described above, in this embodiment, the base 14 is formed by forming the low wettability metal layer 12 on the entire surface of the base body 11 and is covered with the resist layer 15 of the base 14 in the plating step. Although the low contact resistance metal layer 13a and the high wettability metal layer 13b are formed in the portions that are not, the present invention is not limited to this, and as the base 14, the low contact resistance metal layer 13a and the high wettability metal are formed on the entire surface of the base body 11. In the plating step, the low wettability metal layer 12 may be formed on a portion of the substrate 14 that is not covered with the resist layer 15 in the plating process.

  In this case, in the exposure process, the resist layer 15 of the low wettability region formation planned portion 23 is removed from the resist layer 15 by development, and the resist layer 15 of the portion 22 excluding the low wettability region formation planned portion 23 is removed. Is exposed so as to remain. By developing the resist layer 15 exposed in this way, a resist pattern in which the resist layer 15 is present in the portion 22 excluding the low wettability region formation scheduled portion 23 is formed, and the low wettability region planned to be formed in the plating step. Only the portion 23 is plated. Thus, after the resist layer 15 is removed, the metal layers that become the low contact resistance metal layer 13a and the high wettability metal layer 13b are exposed to form the low contact resistance region 2a and the high wettability region 2b. A low wettability region 3 in which the low wettability metal layer 12 is formed is formed on the surface of the metal layer that becomes the metal layer 13a and the high wettability metal layer 13b.

  Further, the base body 11 itself may be used as the base body 14. In this case, the above-described under plating process is omitted, and after the resist layer 15 is formed on the entire surface of the substrate body 11, the exposure process, the development process, the plating process, and the resist removal process are performed as in the present embodiment. For example, when the base body 11 made of copper or copper alloy is used, the surface of the base body 11 functions as a low wettability metal layer. Therefore, in the plating step, the low contact resistance metal layer 13a is the same as in the present embodiment. And the high wettability metal layer 13b is formed. On the contrary, the surface of the base body 11 may be used as the low contact resistance metal layer 13a and the high wettability metal layer 13b, and the low wettability metal layer 12 may be formed in the plating process as described above.

  An electronic component manufacturing method according to another embodiment of the present invention includes the surface treatment method according to the present embodiment, and further includes the following steps. That is, the connector pins 1 subjected to the surface treatment according to this embodiment are packaged in a resin case or the like and assembled as a board mounting connector, and soldered to the circuit board at the solder joints 4. Next, the connector fitting portion 5 is fitted with another pair of connectors soldered to another circuit board. As a result, conduction between the electronic circuits formed on the respective circuit boards is performed, and the manufacture of the electronic component is completed.

  Since the connector pin 1 has the low wettability area | region 3 between the solder joint part 4 and the connector fitting part 5 over the perimeter of the circumferential direction of the elongate part 6, it is to the connector fitting part 5 at the time of soldering Soldering does not occur and deformation of the resin case can be prevented. Further, the connector pin 1 is formed by the surface treatment method of the present embodiment, and unnecessary portions of the metal layer to be the low contact resistance metal layer 13a and the high wettability metal layer 13b are removed by laser light irradiation. Thus, since it is not subjected to heating by laser light irradiation, there is no decrease in spring characteristics, mechanical strength, and the like, and peeling of the low wettability metal layer 12 does not occur. By using such a connector pin 1, a connector having excellent durability can be obtained.

Example 1
A copper plate having a thickness of 0.2 mm is punched out to integrally form a plurality of base body bodies 11, base body support portions 8a, and support frames 10 each having a substantially prismatic longitudinal portion shown in FIG. 9a was obtained. The sum L ′ of the length in the longitudinal direction of the portion that becomes the longitudinal portion 7 of the base body 11 and the length in the longitudinal direction of the base support portion 8a is 3 mm, and the interval W ′ between the portions that become the longitudinal portion 7 is 1 mm. The pitch T ′ between adjacent base body 11 was set to 1 mm. The produced base body 11 was subjected to nickel plating by electrolytic plating to form a nickel plating layer having a thickness of 2 μm as the low wettability metal layer 12. A watt bath was used as the plating bath. As described above, the substrate 14 shown in FIG. 2 was obtained in which the nickel plating layer was formed on the surface of the substrate body 11 made of copper.

Next, a resist layer 15 having a thickness of 8 μm was formed on the entire surface of the nickel plating layer by electrodeposition coating. As the electrodeposition paint, a cation-type negative resist electrodeposition paint (trade name: Elecoat EU-XC, manufactured by Shimizu Corporation) that is cured by ultraviolet irradiation was used. After the formed resist layer 15 is dried, the width D1 of the first mask opening 37 and the width D2 of the second mask opening 38 are set to 250 μm using the exposure apparatus 24 shown in FIG. The resist layer 15 formed in the low wettability region formation planned portion 23 of the longitudinal portion 7 of the base body 14 was exposed and cured over the entire circumference in the circumferential direction of the longitudinal portion 7. For the exposure, ultraviolet rays having a wavelength of 365 nm were used, and the exposure light irradiation amount to the resist layer 15 was set to 150 mJ / cm ² .

  Next, the substrate 14 was immersed in a developer (trade name: DLP-1, manufactured by Shimizu Corporation) to develop the resist layer 15 to form a resist pattern 16. When the formed resist pattern 16 was observed with an electron microscope, the resist layer 15 remained continuously in the middle portion of the longitudinal portion 7 of the substrate 14 over the entire circumference.

  A gold plating layer having a thickness of 0.1 μm is formed as a highly wettable metal layer 13 on a portion of the nickel plating layer that is not covered with the resist layer 15 by electrolytic plating on the substrate 14 on which the resist pattern 16 is formed. Formed. An acidic gold plating bath was used as the plating bath.

  Subsequently, the remaining resist layer 15 was peeled off using a resist stripping solution (trade name: DLP-2, manufactured by Shimizu Corporation) to expose the nickel plating layer. Thereafter, the base 14 was separated from the support frame 10 to obtain the connector pin 1 shown in FIG.

  When the obtained connector pin 1 was observed with an electron microscope, the nickel plating layer was continuously exposed over the entire circumference in the circumferential direction of the longitudinal portion 6 of the connector pin 1, and the low wettability region 3 was formed.

It is a figure which simplifies and shows the structure of the connector pin 1 which is an example of the contact component with which the electronic component manufactured by the manufacturing method of the electronic component of this invention is equipped. It is a figure which shows the state which formed the low wettability metal layer 12 on the surface of the base | substrate body 11. FIG. It is sectional drawing which simplifies and shows the state of the base | substrate 14 in an exposure process. It is a side view which simplifies and shows the structure of the exposure apparatus 24 used suitably for exposure of the resist layer 15. FIG. It is a perspective view which shows the 1st mask part 25 with which the exposure apparatus 24 is provided seeing from a perpendicular upper direction. It is a figure which shows the state after image development of the resist layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Connector pin 2a Low contact resistance area | region 2b High wettability area | region 3 Low wettability area | region 4 Solder joint part 5 Connector fitting part 6,7 Longitudinal part 8 Base support part 9 Strip material 10 Support frame 11 Base body 12 Low wettability Metal layer 13a Low contact resistance metal layer 13b High wettability metal layer 14 Base 15 Resist layer 17 Exposure mask 18 First light source 19 Second light source 23 Low wettability region formation scheduled portion

Claims (8)

A surface treatment method for a substrate having a longitudinal portion, the resist layer forming step of forming a resist layer by electrodeposition coating over the entire surface of the longitudinal portion of the substrate, and the substrate and the substrate so as to face each other Irradiating light from at least two directions with respect to the longitudinal portion of the substrate while relatively displacing the two or more light sources formed , and exposing at least a part of the formed resist layer , An exposure process that exposes the entire circumference of the longitudinal part of the substrate in the circumferential direction, a development process that develops the exposed resist layer to form a resist pattern, and a part of the substrate that is not covered with the resist layer. A surface treatment method comprising: a plating step of performing plating. The longitudinal portion of the substrate is composed of a low wettability metal layer containing at least a low wettability metal having low wettability to solder, and is not covered with the resist layer of the longitudinal portion of the substrate in the plating step. A high wettability metal layer containing a high wettability metal with high wettability with respect to solder is formed on the part by plating, and the plating process further includes a resist removal step of removing the remaining resist layer. The surface treatment method according to claim 1 . The base includes a solder joint and a pair of longitudinal portions extending from the solder joint and extending substantially parallel to each other, and a connector fitting portion is constituted by the end-side portion of the longitudinal portion, and the entire surface of the base Is a substrate having a low wettability metal layer with low wettability to solder, and a resist layer forming step of forming a resist layer by electrodeposition coating over the entire surface of the longitudinal portion of the substrate;
A low wettability region excluding the connector fitting portion and the solder joint portion of the formed resist layer is exposed while relatively displacing the base and two or more light sources provided to face each other with the base interposed therebetween. An exposure step of exposing the low-wettability region of the longitudinal portion of the substrate over the entire circumference in the circumferential direction, and development for developing the exposed resist layer to form a resist pattern in the low-wettability region. 3. The method according to claim 1, comprising: a step of plating a highly wettable metal having high wettability with respect to solder on a portion of the base portion not covered with the resist layer. Surface treatment method. The longitudinal part of the substrate is composed of a highly wettable metal layer containing at least a highly wettable metal with high wettability to solder, and is not covered with the resist layer of the longitudinal part of the substrate in the plating step. A low wettability metal layer containing a low wettability metal having low wettability with respect to solder is formed on the part by plating, and the plating process further includes a resist removal step of removing the remaining resist layer. The surface treatment method according to claim 1 . The surface treatment method according to any one of claims 2 to 4, wherein the low wettability metal includes one or more selected from nickel, cobalt, tungsten, and iron. High wettability metals are gold, gold-nickel alloy, gold-cobalt alloy, gold-nickel-cobalt alloy, gold-silver alloy, silver, copper, palladium, palladium-nickel alloy, rhodium, ruthenium, tin, tin-zinc One or more selected from alloys, tin-silver alloys, tin-copper alloys, tin-bismuth alloys, tin-lead alloys, and alloys of at least two of tin and zinc, silver, copper and bismuth The surface treatment method according to any one of claims 2 to 4, comprising: Method of manufacturing an electronic component, characterized in that the production of electronic parts using the surface treatment method according to any one of claims 1-6. 8. The method of manufacturing an electronic component according to claim 7, wherein the electronic component is a connector, and the contact component of the connector is formed by the surface treatment method.

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